Protective sleeve for slips



2- J. E. ECKEL 2,293,974

7 PROTECTIVE SLEEVE FOR SLIPS Filed March 24, 1941 VI AV 1 M/n INVENTOR.

BY M

ATTORNEY Patented Aug. 25, 1942 PROTECTIVE SLEEVE FOR SLIPS John E.Eckel, Houston, Tex., assignor to Standard Oil Development Company, acorporation of Delaware Application March 24, 1941, SerlalNo. 384,897

1 Claim.

The present invention is directed to a means for protecting slips beforethey are placed in operative position.

In many operations connected with the production of bore holes it isusual to employ slips to hold tools and various portions of theequipment in position. As a specific example, hook wall packers commonlyemployed in cementing for securing strainers in position and for packingofi wells at desired points are secured to the casing or tubing bymeans-of slips. Other types of tools used in other operations are alsocommonly secured in position by slips.

When slips are to be lowered into a drill hole before they are set,there has heretofore been a danger of foreign material entering andjamming them. For example, shale particles produced by the drillingoperations or rubber pieces accidently removed from packers clog theslips while they are in an inoperative position and prevent their properoperation.

It is an object of the present invention to provide slips with meanscapable of preventing the entry of foreign material into the slips aslong I as they are in an inoperative position.

More specifically, it is an object of the present invention to provide aprotective sleeve for slips which wiH prevent the entry of foreignmaterial into the slips and allow them to operate without being hamperedby such particles.

Other objects and advantages of the present invention may be seen from areading of the following description taken with the drawing in whichFig. '1 is an elevation, partly in cross section, showing one embodimentof the present invention, and

Fig. 2 is a fragmentary view illustrating a slight modification of thedevice indicated in Fig. 1.

Referring specifically to Fig. l, packer mandrel I is slidingly arrangedwithin an assembly comprising ring l3, sleeve l6, and 'sleeve 22. Ringl3 and the two sleeves are all secured together to move as a singleunit. Slidingly arranged about sleeve 22 is slip cage I 2 which isprovided with key pin 9 projecting into longitudinal slot 23 of sleeve22. Pin 9 and slot 23 arearranged so that there can be no relativerotative movement between slip cage l2 and the assembly of which sleeve22 forms a part, but only a longitudinal movement is possible betweenthese two bodies.. Slips it are secured to ring l3 through link l5.Sleeve I6 is provided with a upper end of mandrel I0 is provided withbushing 24 adapted to cooperate with the upper portion of slip cage I2in setting the slips, and attached to a lower part is laterallyprojecting pin H arranged to cooperate with J-slot I1.

The assembly thus far described is generally old to the art and its useis well known. The slips may be set at a desired position in a conduitby attaching the mandrel Ill to a string of tubing and lowering theassembly to the desired depth. The wipers or springs is are constructedso that they bear against the conduit with an appreciable tension. Whenthe slips have been lowered to the desired position, the mandrel isrotated to move pin ll out of the transverse portion of J-slot I1, andwhen this rotative movement has been completed, the mandrel ismoveddownwardly until bushing 24 comes in contact with the upper end of slipcage l2. Additional downward movement of the mandrel carries the slipcage along with it and since the slips are held stationary by reason ofthe tension of springs la, the downward movement of the slip cage causesthe slips to move outwardly until they come into engagement with thewall of the conduit and secure the assembly to the wall of the conduitat this point.

The device specifically discussed above and its use are old to theart.In accordance with the present invention, however, a sheet of soft,readily cuttable material is is suitably arranged around the slips. Inattaching them to the specific modification shown in the drawing, thesheet,

of material is attached to ring l3 by means of bolts 20 and to slip cageI2 by means'of screws 2|. In other words, in the application shown sheetI9 is of tubular shape secured at both its ends to the complete assemblyso that it is impossible for foreign material to come in contact withthe slip mechanism to jam it.

In the embodiment illustrated in Fig. 1 the pin 9 and slot 23 preventrelative rotative movement between the ends of sheet IS. The upper endof this sheet is secured to slip cage I2 and the lower end to ring 20,and as previously explained, pin 9 fitting into groove 23 limits thesetwo parts to a relative longitudinal movement only. This is a desirablefeature, but it will be apparent that it is not absolutely necessary inpracticing the invention and that the parts preventing relative rotativemovement between the members secured to the ends of the sheet may beomitted, if desired.

In Fig. 2 a modification is shown in which cor- J-slot l1 and withwipers or springs I8. The responding parts are given like numerals asin 1. In the apparatus illustrated slip cage 12 and ring l3 diameterthan sheet 19, thus protecting the latter from destructive frictionagainst the casing walls.

when the device has been lowered into the bore hole to the desired depthand the assembly manipulated in order to set the slip, the ham teeth ofthe slips readily cut through sheet I! and come in contact with the wallof the conduit to securely fasten the slips thereto.

It is preferred to make sleeve I! out of soft, thin and readily cuttablematerial. It has been found that thin rubber sheet is a suitablematerial of which to construct the protective means of the presentinvention, but other materials, such as sheet lead, are also suitable.

, For the purpose of illustrating the invention the protective device isshown applied to a particular embodiment of hook wall slips. Such slipsare conventionally secured to packers on other bore hole tools. Ashowing of a specific tool secured to the slips has been omitted inorder to simplify the description of the invention. It will be manifest,moreover, that the application of the protective device is not limitedto the specific hook wall illustrated, but may be applied to any slipswhich are to be operated after they have are provided withcircumferential projections 25-25 which are slightly larger inbeenplaced in position and particularly to slips suitable for use withvarious bore hole tools which must be lowered into bore holes beforebeing operated.

Moreover, while specific examples of suitable ent invention, what isclaimed as new and useful and is desired to be secured by Letters Patentis:

A protective device for a slip assembly comp i in slips arranged to movesaid slips into operative and inoperative positions, a protective devicecomprising a thin sheet of readily cuttable material secured to saidslip assembly arranged to cover the cutting edges of said slips and toprevent the entry of articles of foreign materials between said sheetand said assembly, projections arranged on said, slip assembly above andbelow the sheet whereby the sheet is protected from destructive frictionagainst bore hole walls.

JOHN E.

in combination. a slip assembly including

